Isocyanate Crosslinkers: Adapting To Change In Leather Finishing

摘要

Since their introduction into the market for leather finishing in the late 1980s, crosslinkers based on isocyanate chemistry have continuously strengthened their position as materials of choice for high-end finishing, most importantly for automotive applications. Developments continue that provide high performance from solvent-free aqueous based systems. Isocyanates currently experience no significant competition from other crosslinker systems based on epoxy, aziridine, or carbodiimide chemistry. This is due to an excellent property profile with regard to processability, but also to the quality of the resulting leather and leather goods. As aliphatic isocyanates are employed exclusively, the finish does not suffer from thermally or UV-induced yellowing and other severe aging symptoms. Furthermore, as the isocyanate groups are completely converted (e.g. into urethane or urea functionalities) during the hardening process of the coating, they are effectively prevented from compromising the health of the end users or the environment. This is in clear contrast to coatings from other starting materials, which, for example, may contain highly reactive and irritating amines.